Stack switch



v `May 13 1941 B. E. sHAw 2,241,748

STACK SWITCH Filed Sept. 11, 1939 2 Sheets-Sheet 1 I III Inl. Il'

B. E. SHAW STACK SWITCH May'l, 1941.

Filed Sept. ll, 1939 2 Sheets-Sheet 2 Patented May 13, 1941 auraiss'rAcx swrrcn Burton E. Shaw, Bristol, Ind., assignor to Penn ElectricSwitch Co., Goshen. Ind., a corporation of Iowa Application September11, 1939, Serial No. 294,408

(CL 20o-138) 6Claims.

An object of my present invention is to provide'a stack switch includinga switch structure and a relay, together with a transformer for variouscircuits of the stack switch, the parts being of simple construction andof such design that the switch can be made comparatively small andinexpensive from a. manufacturing standpoint.

A further object is to provide a stack switch having improved featuresof construction whereby better operation characteristics of the stackswitch are obtained at less power consumption than in standard stackswitches as found on the present-day market.

Another object is to provide a stack switch which includes a switchingmechanism formed of a buckled leaf spring having an extension thatcontacts with the periphery of a notched disc which is controlled inaccordance with temperature changes in the stack, the arrangement beingsuch that very little power is needed to operate the switch from oneposition to the other, so that the motion of the temperaure responsiveelement may be substantially magnified and yet snap action is secured toinsure quick make and break, and eliminate the possibility of thecontacts being jarred open by operation of the relay in the stackswitch.

Still another object is to provide a relay which can be madesuiliciently powerful, yet rel-atively small, to minimize currentconsumption and to minimize jarring of the stack switch as a result ofoperation of the relay from one position to the other.

More particularly, it is my object to provide a relay which has a solidcore and a shading coil serving in addition to its shading coil capacityas a spacer between the relay and a panel on which the relay is mounted.n

Among other objects of the invention, I provide a panel for the stackswitch mechanism and the relay which is supported in position by atransformer supporting bracket and a pair of screws which retain thebracket in supported position, the panel and the bracket cooperatingwith each other and with the casing for the stack switch in such mannerthat the parts may be placed in their proper relative positions and thenall of them held there by the mere insertion of two screws.

A further object is to provide a relay which has a hard silicon steelcore and therefore loses all residual magnetism when current isdiscontinued, thus making it possible. by using hard-silicon `for amagnetic frame of the relay and an arma- -l ture thereof, to permit thearmature to touch the frame in closed position so that there is amaximum of holding power to guard against undesired opening of the relayas a result of voltage drop.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of mydevice whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in my claims and illustrated in theaccompanying drawings. Although the invention is susceptible of avariety of embodiments, it is unnecessary to fully describe andillustrate more than one in order to give a full understanding of theinvention both from its structural and functional standpoints.Accordingly, I have illustrated a preferred and desirable embodiment ofthe invention in the accompanying drawings, in which:

Figure l is a front elevation of a stack switch embodying my invention,with the cover removed to show interior construction details;

Figure 2 is an enlarged sectional view on the line 2 2 of Figure 1showing a switch mechanism actuated by a stack temperature responsiveelement. The switch is in closed position;

Fig. 3 is a view similar to Fis. 2 showing the switch in open position;

Figure 4 is an enlarged sectional view on the line 4-4 of Figure 1showing relay mechanism of my stack switch. 'I'he relay is in opencircuit position.

Figure 5 is a similar sectional view showing the relay in closedposition;

Figure 6 is a sectional view on the line 6-6 of Figure 5;

Figure 7 is a perspective view of a. combined spacer and shading coil,and

Figures 8 and 9 are sectional views on the lines 8--8 and 9-9 of Figure4.

In the accompanying drawings, I have used the reference numeral I0 toindicate generally a casing. A tubular support I2 extends from thecasing I0. A coiled bimetallic element I3 has one end connected to thetube I2 at I4 and its other end secured to an actuating rod I5. Thebimetal element I3 is adapted tobe inserted in the stack of an oil orgas burning furnace so as to respond to the temperature therein.

Within the casing I0, a disc I6 having a notched periphery is mounted onthe rod I5. A panel i1 is supported in the casingl and has a notch I8through which a portion of the disc I6 extends to cooperate with anextension I9 0f a contact spring 20.

The contact spring is mounted in buckled position between upper andlower arms 2I and 22 of va bracket 23. The spring 20 is buckledsuiliciently to normally retain a contact 24 carried thereby against astop screw 25. Opposite the stop screw 25 is a cooperating stationarycontact 26 carried by a bracket 21.

Therextension I9 is U shaped, as shown in Figures 2 and 3, having aterminal end 28 adapted to contact with the periphery ofthe notched discI6. The terminal end 28 may be adjusted toward or away from the disc forproper operation of the stack switch contacts 2 4--23 by means of anadjusting screw 29. The U shaped extension I9 has an inherent tendencyto contract in width and may be expanded or permitted to contract byrotating the adjusting screw 29 in the proper direction. As shown bydotted lines in Figure 2, as the disc I6 continues to rotatecounterclockwise it will spring the extension I9 and the spring 29 andpermit the notches of the disc to slip past the extension i9 withoutbreaking the circuit across the contacts 24-26. Immediately upon reverserotation of the disc, the switch will be thrown to the other position,as shown by solid lines in Figure 3. Upon continued rotation in aclockwise direction, the notched disc`will slip past the extension I9,keeping the contacts` open as illustrated by dotted lines.

The panel I1 at its upper endy has a pair of projections 39 extendingthrough perforations 3I in the casing I0 (see Figures liand 2). Thispositions the upper end of the panel, while the lower end thereof ispositioned by resting on a seat 32 of a bracket 33. The back end of thebracket .has a pair o f projections 34 entering openings 35 of the backof the casing I0, as shown in Figure 3. The bracket 33 also has a pairof.

threaded ears 36'receiving screws 31 extended through the walls of thecasing I0.`

The bracket 33 has a pair of downwardly extending portions 39 (seeFigure l) terminating in perforated ears to receive screws 39 forsupporting a transformer T. 'I'he bracket 33 accordingly serves boththepurpose of a support for the transformer and a means cooperating withthe casing I0 and the panel I1 to position the panel; the screws 31,when they are inserted in position, eilecting retention of all the parts33, T and- I1 in their proper relation to the casing I0.

On the panel I1, I provide a safety switch SS, described in mycopending' application, Serial No. 294,409 filed September 11, 1939 andwhich therefore will notl be described further in this application.

VOn the back of the panel I1, I mounta relay consisting of a coil 40, acore 4I, a magnetic .frame member 42 and an armature 43. A nonmagneticframe member 44 of brass or the like is secured to the core 4I byriveting the core as indicated at 45. 'I'his also retains the magneticframe member42 on the core.

tongue may-bebent downwardly, as shown by dotted lines in Figure 4, toincrease the tension of the spring 49 without the necessity of having toprovide an adjusting screw for this purpose.

The frame member 44 has a ilngerlike extension 5I bent to a positionabove the armature 43 to act as a stop therefor, as shown in Figures 4and 6.

On the front of the panel I1 are a pair of stationary power contacts 52and a stationary low voltage contact 53. Cooperating therewith are apair of movable contacts 54 and a single movable contact 55. Thecontacts 54 and 55 are carried by contact leaf springs 56 and 51. Thespring `51 is secured to the armature 43 under a block of insulation 58,while the spring 53 is riveted to the upper end of the block as at 59.The block 53 is secured to the armature 43 by a pair of rivets 58a.

The leaves 56 and 51 extend through openings 60 and 5I of the panel I1so as to expose the contacts 54 and 55 on the front thereof where theyare readily accessible for inspection and cleaning. The leaves 56 and 51are substantially straight, thus eliminating the necessity of bendingdies for forming them, and the spring 58 is T-shaped, as shown in Figure6, so as to provide a bridging contact for the contacts 52. The T headarrangement of the spring 53v provides substantially equal contactpressure on both contacts 52 when the relay is in closed circuitposition. The contacts 54 being mounted sub- -stantially above the pivotof the armature 43 on the shoulders 48, give a good wipe to thesecontacts relative to the contacts 52 to keep them clean.

The core 4I is made of hard silicon steel, which requires no machiningand `loses all residual magnetism when the coil 40 is de-energized. Theframe member 42 and the armature .43 are likewise made of hard siliconsteel, to provide for a maximum of loss of residual magnetism. Thismakes it possible to have the armature contact the frame 42 at the point80, illustrated in Figure 8, when the relay is ,in closed position.Since contact of the parts gives maximum attraction, this arrangementrequires a considerable reductionin line voltage before the relay dropsout. Hard silicon steel also has the characteristic of requiring lesscurrent for operation, and therefore the coil 49 may be made relativelysmall.

To minimize eddy currents, a shading coil SC is provided consisting of apiece of copper formed Screws B8 extend through the panel and arethreaded into the frame member 42, the leg 3.5

' of the shading coil being notched at 31 to proout departing from thespirit and scope of the invention as set forth in the appended claims.

What I claim as my invention and desire to secure by Letters Patent ofthe United States is: 1. In a stack switch, a casing, a notched disc insaid casing. a switch coacting therewith, temperature responsive meansfor rotating said disc, said switch comprising a buckled leaf, a contactcarried thereby, a stationary contact for engagement therewith, a.projection from said buckled leaf, said projection being U-shaped, anadjusting screw carried thereby to open or close the U, the free end ofsaid projection engaging the periphery of said notched disc to be swungin one direction or the other by rotation of the disc in oppositedirections and consequent movement of said buckled leaf with snap actionfrom one circuit controlling position tothe other.

2. In a stack switch, a notched disc, a switch coacting therewith,temperature responsive means for rotating said disc, said switchcomprising a buckled spring leaf, a contact carried thereby, astationary contact for engagement therewith, a projection from the sideof said buckled leaf, a disc engaging element on the free end of saidprojection and engaging the periphery of said notched disc to be swungin one direction or the other by rotation of the disc in oppositedirections and consequent movement of said projection and thereby saidbuckled leaf with snap action from one circuit controlling position tothe other.

3. In'a stack switch, a notched disc, temperature responsive means forrotating said disc, a switch comprising a buckled leaf, a contactcarried thereby, a stationary contact for engagement therewith and aprojection from said buckled leaf, said projection being U shaped, anadjusting screw carried thereby to open or close the U, the free end ofsaid projection engaging the periphery of said notched disc to be swungin one direction or the other by rotation of the disc in oppositedirections.

4. In a stack switch, a notched disc, temperature responsive means forrotating said disc, a switch comprising a buckled leaf, coactingcontacts controlled by swinging thereof in opposite directions, aprojection from one side of said buckled leaf, a U-shaped element havingone arm connected to said projection and its other arm engaging theperiphery of said notched disc to be swung by rotation of the disc inopposite directions and thereby effect movement of said buckled leafwith snap action from a position with said contacts open to one withthem closed or vice versa.

5. In a stack switch, temperature responsive means, a disc rotatablethereby, a switch comprising a buckled leaf, a contact carried thereby,a stationary contact for engagement with said contact of said leaf, areturn bent projection from said buckled leaf, an adjustingA screw foradjusting the distance between the sides of said return bent projection,the free end of said projection engaging the periphery of said notcheddisc to be swimg on one direction or the other by rotation of the discinA opposite directions, and subsequent movement of said buckled leafwith snap action from one circuit controlling position to the other.

6. In a switch structure, a notched disc, temperature responsive meansfor rotating said disc, a switch comprising a buckled spring leaf,coacting contacts controlled by buckling thereof in opposite directions.and a U-shaped element having one ann secured to said buckled leaf andits other arm engaging the periphery of said notched disc to be swung byrotation of the disc in opposite directions and effect movement of saidbuckled leaf with snap action.

BURTON E. SHAW.

